OUR OWN HIGH SCHOOL, DUBAI

CHEMISTRY
QUESTION BANK-GRADE-12
CHAPTER-10: BIOMOLECULES
SECTION – A
The following questions are multiple-choice questions with one correct answer.
Each question carries 1 mark.
1 [1]
The disaccharide found abundantly in nature is
a) sucrose b) maltose c) lactose d) galactose

2 [1]
The change in specific rotation with time, observed in the case of glucose is called
a) specific rotation b) inversion c) muta-rotation d) auto rotation

3 [1]
Carbohydrates are stored in our body in the form of
a) Fructose b) glycogen c) starch d) lactose

4 [1]
In proteins different amino acids are bonded by
a) single bonds b) glycosidic bond c) peptide bond d) hydrogen bonds

5 [1]
Oxygen transport in our body requires the protein
a) Hemoglobin b) Insulin c) Myoglobin d) enzymes

6 [1]
Primary structure of protein refers to
a) the sequence in which amino acids are linked together
b) the nature of the side chains attached to main chain
c) the number of amino acid units linked together
d) the minimum number of amino acid units to be linked to form the protein

7 [1]
Secondary structures are
a) α- helix structures b)  - pleated structures c) α- helix or  pleated structures
d) structures with hydrogen bonding and as a result, always elastic

8 [1]
In hemoglobin, the polypeptide chains are folded into a compact form and this is called
a) primary bonds b) secondary structure c) tertiary structure d) none of these

9 [1]
The helical structure of proteins is stabilised by
a) Hydrogen bonds b) vander Waals force c) peptide bondsd) multiple peptide bonds

10 [1]
Proteins are polyamides of
a) α – amino acids b)  - amino acids c) α – hydroxy acid d) - hydroxy acid

11 [1]
Sickle cell anaemia is caused by a change in the
a) primary structure of hemoglobin b) secondary structure of hemoglobin
c) denaturation of protein in blood d) Tertiary structure of DNA

12 [1]
Which of the following is an example of Zwitter ion?
a) glycine hydrochloride b) Ammonium acetate c) Alanine d) none of these
13 [1]
In nucleic acids, the sequence is
a) Sugar-Base-Phosphate b) Base-Sugar-Phosphate
c) Phosphate-Base-Sugar d) Base-Phosphate-Sugar

14 [1]
The base present in RNA, but not found in DNA is
a) Thymine b) Uracil c) Guanine d) Adenine

15 [1]
The function of DNA is to
a) synthesis proteins b) Synthesis RNA c) to carry hereditary characters d) all the above

16 [1]
Both DNA and RNA contain the purine base
a) Guanine and adenine b) Adenine and thymine
c) Guanine and uracil d) Uracil and cytosine

17 [1]
DNA and RNA have the common bases
a) Adenine, thymine, uracil b) guanine, thymine, uracil
c) guanine, adenine, cytosine d) Adenine, cytosine, uracil

18 [1]
Hydrogen bond formation occurs in DNA between
a) cytosine and thymine b) thymine and guanine
c) thymine and adenine d) thymine and uracil

19 [1]
The helices of DNA are held together by
a) Hydrogen bond b) Ionic bond c) vander Waals bond d) covalent bond

20 [1]
Nucleic acids are
a) polymers of nucleosides b) polymers of nucleotides
c) polymers of purine bases via phosphate ester bonds d) Phosphate ester bonds

SECTION – B
The questions in this section are Assertion – Reason type of questions

21 Assertion (A): Acetic acid is not a carbohydrate. [1]

Reason (R): Acetic acid fits into general formula of carbohydrate, ie. Cx(H2O)y.

22 Assertion (A): Glucose does not form the hydrogen bisulphite addition product. [1]
Reason (R): Glucose is not so reactive to form the product with NaHSO3

23 Assertion (A): Two sugar units are joined by 1,2- glycosidic bond in sucrose. [1]
Reason (R): It contains C1- glucose and C2- fructose glycosidic bond.

24 Assertion (A): Sucrose is dextrorotatory. [1]

Reason (R): Sucrose on hydrolysis gives dextrorotatory glucose (+52.5o) and laevorotatory fructose
(-92.4o).

25 Assertion (A): α –glycosidic linkage is present in maltose. [1]

Reason (R): Maltose is composed of two glucose units in which C1 of one glucose unit is linked to C4
of another glucose unit.

26 Assertion (A): All naturally occurring α –amino acids except glycine are optically active. [1]
 Reason (R): Most naturally occurring amino acids have L-configuration.

27 Assertion (A): Vitamins B and C must be supplied regularly in the diet. [1]
Reason (R): Vitamins B and C are soluble in water which are readily excreted through urine and
cannot be stored (except vitamin B12) in our body.

28 Assertion (A): The two strands of DNA are complementary to each other. [1]
Reason (R): Adenine forms hydrogen bonds with guanine and thymine form hydrogen bonds with
cytosine.

29 Assertion (A): α - helix structure of proteins is in the shape of right-handed screw. [1]
Reason (R): There is hydrogen bond between the group of each amino acid to the
of an adjacent turn of the helix.

30 Assertion (A): Tryptophan is an example of non-essential amino acid. [1]

Reason (R): The amino acids that are not synthesized in human body are essential amino acids.

SECTION - C
The following questions are very short answer type and you may answer them in minimum two
sentences.

31 (i) What type of bonding helps in stabilising the a-helix structure of proteins? [2]
(ii) What is the structural difference between a nucleoside and a nucleotide?

32 Write the reaction involved when D-glucose is treated with the following reagents: [2]
(a) HCN (b) Br2 water

33 Write the reactions involved when D-glucose is treated with the following reagents. [2]
(a) HI (b) H2N OH

34 Write the main structural difference between DNA & RNA. And name the base present in DNA. [2]

35 Write any two reactions of glucose which cannot be explained by open chain structure. [2]

36 What is meant by (i)Peptide linkage? (ii) glycosidic linkage? [2]

37 What is essentially the difference between α-form of glucose and β- form of glucose? Explain. [2]

38 State what you understand by primary structure and secondary structure of proteins. [2]

39 What are vitamins? How are they classified? [2]

40 Name the bases present in RNA. Which one of these is not present in DNA? [2]

SECTION – D
The following questions are short answer type and you may answer them in minimum three
sentences.

41 (i) Which one of the following is a disaccharide: Starch, maltose, fructose, glucose? [3]
(ii) What is the difference between acidic amino acid and basic amino acid?
(iii) Write the name of the linkage joining two nucleotides.

42 (i) Which one of the following is an oligosaccharide: Starch, maltose, Fructose, glucose? [3]
 (ii) What is the difference between DNA and RNA.
(iii) Write the name of the disease caused by the deficiency of vitamin B1.

43 (i) Write the product obtained when D-glucose reacts with HCN. [3]
(ii) What type of bonding stabilizes the α-helix structure of proteins?
(iii) Write the name of the disease caused by the deficiency of vitamin C.

44 (i) Which one of the following is a polysaccharide: Starch, maltose, fructose, glucose? [3]
(ii) What is the difference between fibrous protein and globular protein?
(iii) Write the name of vitamin whose deficiency causes bone deformation in children.

45 (i) Which one of the following is a monosaccharide: Starch, maltose, lactose, glucose? [3]
(ii) Write one difference between α-helix and β-pleated sheet structures of protein.
(iii) Write the name of the disease caused by the deficiency of vitamin D..

SECTION – E
The following are long answer type questions/Case Based Questions

46 (i) What is essentially the difference between α-glucose & β-glucose? What is meant by pyranose [5]
structure of glucose?
(ii) What is glycogen? How is it different from starch? How is starch structurally different from
cellulose?

47 (i) “The two strands of DNA are not identical but are complementary.” Explain. [5]
(ii) Amino acids may be acidic, alkaline or neutral. How does this happen? What are essential and
non – essential amino acids? Name one of each type.

48 (i) Deficiency of which vitamin causes rickets? [5]

(ii) Distinguish between fibrous protein and globular protein with examples.
(iii) What type of linkage is responsible for the formation of proteins?
(iv) Write the product formed when glucose is treated with HI and HNO3.

49 Read the passage and answer the questions that follow: [4]
Shanti, a domestic helper of Mrs. Anuradha, fainted while mopping the floor. Mrs. Anuradha
immediately took her to the nearby hospital where she was diagnosed to be severely ‘anaemic’. The
doctor prescribed an iron rich diet and multivitamins supplement to her. Mrs. Anuradha supported
here financially to get the medicines. After a month, Shanti was diagnosed to be normal
After reading the above passage, answer the following questions:

(i) Name the vitamin whose deficiency causes ‘pernicious anaemia’. [1]

(ii) Give an example of a water – soluble vitamin. [1]

(iii) Name the B – group vitamin that is not water soluble. [1]

(iv) What are the diseases caused by the deficiency of Vitamin – D? [1]

50 Read the passage and answer the questions that follow: [4]
Peptide linkages are the bridges connecting the amino acids in the making of a protein. The reaction
between two molecules of similar or different amino acids, proceeds through the combination of
 the amino group of one molecule with the carboxyl group of the other. The product of the reaction
is called a dipeptide because it is made up of two amino acids. For example, when carboxyl group of
glycine combines with the amino group of alanine we get a dipeptide, glycylalanine.

(i) Show the difference between peptide linkage and glyosidic linkage. [1]

(ii) Show the formation of glycylalanine. [1]

(iii) On the basis of molecular shapes how proteins are classified? How do they differ? Give one [2]
example each.

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